GOI’s precise skill challenges combined with the potentially unlimited penalty for failure creates an environment where inevitably, no matter how far along you are, you will eventually repeat the entire game from scratch, just to get back to where you were. Because there are no checkpoints, this means you can easily restart the whole game in a matter of seconds, no matter how high up you are. This means that if you fall, you’ll land on an earlier section. GOI has one level, shaped like a big cone that spreads out as it rises up, having you cross over your earlier paths as you ascend, creating horseshoe shaped level design. Playing the game at all with it’s strange and difficult control scheme seems impossible, so redoing the incredibly precise tricks it has you perform can seem impossible. GOI can be incredibly frustrating, because there are no permanent checkpoints, and many of the toughest challenges set you up to lose massive amounts of progress. This method of control is incredibly sensitive, and fiddly, but the game ramps up to requiring you to use it in extremely precise and demanding circumstances, at high risk of losing your progress.
With this control scheme you can push and pull yourself along the ground, pull yourself up using holds, fling yourself, swing under holds, pogo to launch yourself, and so on.
The only mechanic is moving around a hammer, attached to a man in a cauldron. Getting Over It With Bennett Foddy (GOI for short) is the absolute limit of how far you can get with a single game mechanic.